Field of the Invention
This invention relates generally to decorative laminates. More particularly, this invention relates to decorative laminates incorporating a plurality of printed patterns of different colors which are visibly luminescent simultaneously upon exposure to ultraviolet light, and to methods of producing the same.
Background Information
Decorative laminates typically include a core layer and a decorative layer. The core layer in general is a supporting layer onto which the decorative layer is bonded. In typical high heat and pressure laminates, the core layer comprises a plurality of cellulosic sheets made from a kraft paper impregnated with a laminating resin. Such laminating resins may include, for example, phenolic, melamine, amino, epoxy, polyester, silicone, and diallyl phthalate. A preferred laminating resin for the core layer is a phenolic resin made from the reaction of phenols with formaldehyde.
The decorative layer is typically formed from one or more sheets of cellulose pigmented paper containing a printed image, pattern, grain design or a solid color, which oftentimes has been impregnated with a transparent resin. Such resins may include, for example, melamine, amino, epoxy, polyester, silicone, and diallyl phthalate. A preferred resin for the decorative layer papers is melamine-formaldehyde which, when cured, is colorless, resistant to light and heat, and resistant to a variety of solvents and stains. The decorative layer may also be “dry”—that is, lacking any impregnating resin. The printed image is something that can be seen in normal light; i.e., when the decorative layer is subjected to visible light (the portion of the electromagnetic spectrum that is visible to the human eye; e.g., about 400-700 nm) the printed image can be seen by the human eye.
When the decorative layer includes a printed pattern and is used in certain applications (e.g., bowling lanes), it is commonly covered with an overlay layer, which is typically a high-quality alpha cellulose paper impregnated with a melamine-formaldehyde resin. The overlay layer helps to protect the decorative layer from external abuse such as impact from objects, abrasive wear and tear, harsh chemicals, burns, spills and the like. The melamine-formaldehyde resin primarily accounts for these protective properties of the laminate. The alpha-cellulose paper: 1) acts as a translucent carrier for the water-thin resin; 2) imparts strength to the melamine-formaldehyde resin; 3) maintains a uniform resin thickness in the overlay layer by acting as a shim; and 4) controls resin flow.
The core layer, the decorative layer and, when utilized, the overlay layer, are typically stacked in a superimposed relationship, between steel press plates and subjected to elevated pressure and temperature for a time sufficient to cure the laminating resins impregnating the respective layers. The elevated temperature and pressure cause the impregnated resins to flow, which consolidates the stack into an integral mass that is the laminate. These laminates can be used in numerous applications, including bowling lanes, floors, counter tops, table tops, furniture, store fixtures, and the like. Examples of conventional high pressure decorative laminates are disclosed in U.S. Pat. Nos. 3,418,189; 4,311,748; 4,473,613; and 4,741,968.
It is also known to provide a decorative laminate with an image or pattern printed on one or more of the sheets comprising the laminate using a photoluminescent material. When exposed to ultraviolet light, the image or pattern visibly luminesces. See for example, U.S. Pat. Nos. 6,596,416 and 6,395,408, which are hereby incorporated by reference. Disclosed therein is a single image or pattern of a single color. When such a decorative laminate is used, for example, in bowling lane applications, the single color image or pattern limits the applications for which the laminate can be used. Further it is known to utilize aluminum oxide within the overlay layer to contribute to its wear-resistant qualities. However, the aluminum oxide tends to cause undesirable scuffing and wear to the bowling ball and to the soles of the shoes worn by the bowler. What is needed is a decorative laminate for use in, for example, bowling lanes, where a plurality of printed images or patterns, made from photoluminescent materials of different colors, are visibly luminescent simultaneously when exposed to ultraviolet light, against a backdrop of a single color that is also visibly luminescent simultaneously when exposed to ultraviolet light, thereby providing a relatively greater amount of visual information to the bowler to add to the safety and enjoyment of the bowling experience. What is also needed is an overlay layer less apt to scuff and wear items in contact with the laminate; e.g., bowling balls, bowling shoes, etc.